Help with search for Persons who graduated from particular course/specific year.

Hope this is in the correct forum.
I am about to conduct some research for a Msc. I am looking to contact people from the undergraduate course for which I am doing the MSc, but who graduated in 1999.
The alumni office of the college only has contact information for a small number of those that graduated - and this is the only group the college will forward questionnaires to on my behalf.
I am wondering if there is another method to try and track them down. I have tried linkedin and facebook but you cannot be specific enough with the course and year - or so it appears to me.

Many thanks to anyone who has any innovative ideas to try and track this group down.

an Irish Times personal ad?

What about the education forum on boards.ie?

Is there an alumni association newsletter ? If so, an ad or letter in that would hopefully be read by enough people to get the message out there ( Having said that, I graduated 21 years ago, and once a year for 21 years now, my parents hand me a letter from the Alumni association and I bin it without opening it, but maybe some people read it).

Thanks for the suggestions, I have now just out a post on the Ed forum on Boards so hopefully get something there.
Huskerdu that is what I am afraid off when I sent the questionnaires out via the alumni office. You obviously didn't think back to when you might have needed assistance from past graduates if it arose for you.
Thanks again.